I took my 2013 370Z to Laguna Seca this year and my comments are as follows;
I think GT did a great job of teaching me the track, showing me a good line (but not the best line) around the track, and giving me a rough estimate of corner speeds and an expected lap time.
I will say that the physics of the game did NOT do anything in preparing me for real life laps, though... there is nothing like real life g-forces and the adrenaline of putting your life at risk - you just don't get those in a game.
I think GT did a great job of teaching me the track, showing me a good line (but not the best line) around the track, and giving me a rough estimate of corner speeds and an expected lap time.
I will say that the physics of the game did NOT do anything in preparing me for real life laps, though... there is nothing like real life g-forces and the adrenaline of putting your life at risk - you just don't get those in a game.